Contact arrangement with contact pieces guided towards each other and are displaced in a longitudinal manner and a roller-type contacts for making contact in one such contact arrangement

ABSTRACT

In order to simplify the construction and to reduce the size of a contact arrangement ( 1 ) comprising at least one outer contact piece ( 3 ) and at least one inner contact piece ( 5 ) which are guided towards each other such that they can be displaced in a longitudinal manner, also comprising a roller-type contact ( 2 ) provided with contact rollers ( 7 ), arranged for electrically conductive connection between the inner contact piece ( 5 ) and the outer contact piece ( 3 ), the or at least one outer contact piece ( 3 ) comprises a recess ( 4 ) with a concave cross-sectional defining wall, wherein the rolling contact is at least partially arranged ( 2 ) for the transfer of current. The invention also relates to a roller-type contact ( 2 ) for one such contact arrangement.

CLAIM FOR PRIORITY

This application is a national stage application under 371 based onPCT/DE03/00621, published in the German language on Sep. 4, 2003, whichclaims priority to German Application No. 102 08 704.0, which was filedon Feb. 25, 2002.

TECHNICAL FIELD OF THE INVENTION

The invention relates to a contact arrangement with contact piecesguided to move in a longitudinal direction and to a roller-type contactfor making contact in such an arrangement.

BACKGROUND OF THE INVENTION

A contact arrangement and such a roller-type contact are disclosed inthe German utility model G 93 00 421.4. The roller-type contact known todate has contact rollers which are arranged at both ends of a contactbolt, which can move in its longitudinal direction, between twostationary contact bolts, each contact roller resting with twofrustoconical rolling bodies on the one hand against the moveablecontact bolt and on the other hand against one of the stationary contactbolts. In order to guide the moveable contact bolt such that it can movein the longitudinal direction, the rolling bodies are arranged such thatthey can rotate freely on a rotation axis which has two end flanges atits ends. Furthermore, two prestressed helical springs are providedwhich are supported on the one hand on the end flanges and on the otherhand on the rolling bodies, which produces a pressure force for therolling bodies on the contact bolts which is required for making thecontact. The rolling bodies are produced from an electrically conductivematerial, which means that the contact bolts are electrically connectedto one another. The contact arrangement known to date comprises thecontact pieces and the contact rollers arranged in pairs.

The contact arrangement known to date has the disadvantage thatindispensable, additional shielding elements are required to shield thecontact point between the roller-type contact and the contact bolt inrespect of the wear which takes places as well as for safety reasons.This makes the design of power electronics modules more expensive andresults in complex assemblies.

SUMMARY OF THE INVENTION

The invention relates to a contact arrangement having at least one outercontact piece and at least one inner contact piece, which are guidedsuch that they can move in the longitudinal direction with respect toone another, and having a roller-type contact, which has contact rollersand is arranged between the inner contact piece and the outer contactpiece so as to make the electrically conductive connection.

The invention also relates to a roller-type contact for making contactbetween at least one outer contact piece and at least one inner contactpiece, which are guided such they can move in a displacement directionwith respect to one another, the roller-type contact having at least onecontact roller which has rolling bodies, which rest against the oragainst one of the outer contact pieces and against the or against oneof the inner contact pieces and connects said outer and inner contactpieces electrically conductively to one another, at least one springelement for providing the necessary pressure force for the rollingbodies, and a rotation axis.

The invention therefore provide sa contact arrangement of the typementioned initially which has a simple and compact design.

The invention also provides a roller-type contact of the type mentionedinitially which can be used in a contact arrangement according to theinvention.

In one embodiment of the invention, at least one of the outer contactpieces has a cutout having a limit wall which is concave in crosssection, the roller-type contact being arranged at least partially inthe cutout for transferring the current.

In the roller-type contact embodiment, the spring element is acompression spring which is arranged between the rolling bodies.

Owing to the arrangement of the spring element between the rollingbodies, the rolling bodies are no longer pressed inwards from theoutside, as in the prior art, but, conversely, are pressed outwards fromthe inside. Owing to this design measure, it is now possible for theroller-type contacts to be used in the inner region of an outer contactpiece which is at least partially concave in cross section. The innercontact piece may also protrude at least partially into the innerregion. The spring element therefore presses the rolling bodies on theone hand against the concave inner wall of the cutout of the outercontact piece and on the other hand against the outer surface of theinner contact piece. In this case, the contact arrangement is shieldedfrom the outside by the outer contact piece owing to the encapsulationproduced. According to the invention, additional shielding of the entirecontact arrangement is thus dispensed with, which improves theproduction, design and compactness of the overall assembly.

In one preferred embodiment of the invention, the outer contact piece isa stationary contact tube, in which the inner contact piece is arrangedas a contact bolt which is guided such that it can move in thelongitudinal direction. In this embodiment, the cutout is thus theinterior of a hollow-cylindrical and thus concave contact tube. Theconcave inner wall or limit wall of the outer contact piece is sealedaround the circumference in this embodiment, which further improves theencapsulation or shielding of the contact arrangement.

In another embodiment, the contact bolt has, at mutually opposing ends,longitudinal grooves which are concave in cross section and are eachprovided for accommodating contact rollers. Owing to a likewise concavedesign such as this of the inner contact piece, contact faces of therolling bodies brush over both contact faces of the outer contact pieceand contact faces of the inner contact piece when the rolling bodies arecompletely rotated. A transverse offset of these contact faces which isotherwise required is dispensed with in this embodiment, which increasesthe overall size of the contact faces.

In an alternative embodiment, the outer contact piece is a stationarycontact tube, in which the inner contact piece is guided such that itcan move in the longitudinal direction, the inner contact piece having acontour which is star-shaped in cross section, such that subregions aredelimited between the inner contact piece and the contact tube, thecontact rollers being arranged in said subregions. In this embodiment,at least three subregions are arranged around the circumference of theinner contact piece which can move in the longitudinal direction, whichfor one thing improves the guidance of this contact piece. Furthermore,however, the contact face between the roller-type contacts and thecontact pieces is also increased in size, which reduces the extent towhich the contact arrangement is heated.

In still another embodiment, the longitudinal grooves have a curvaturein cross section, whose radius is equal to the radius of the contacttube. This design measure prevents contact faces which are offset withrespect to one another in cross section on the contact rollers.

In one advantageous embodiment of the roller-type contact according tothe invention, the rolling bodies are in the form of collars, whichmakes it possible to use inner contact pieces which have a star-shapedcontour in cross section and delimit at least three subregions within acontact tube.

In an alternative embodiment, the rolling bodies may be frustoconical.This embodiment is particularly advantageous when the inner contactpiece is in the form of a cylindrical contact bolt and has longitudinalgrooves, which are round in cross section and are provided in each casefor accommodating the roller-type contact, at both of its ends.

The roller-type contact according to the invention may be comprised of acontact roller or of two or more contact rollers, which are connected toone another via a connection device, the connection device having noinfluence on the ability of the rolling bodies to roll.

According to the invention, any compression springs may be used. Helicalsprings, spiral springs, disk springs, elastomer springs or pneumaticsprings are mentioned by way of example.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments and advantages of the invention are described below in moredetail with reference to the figures in the drawings, in which:

FIG. 1 shows a perspective illustration of an exemplary embodiment ofthe contact arrangement according to the invention having a roller-typecontact according to the invention.

FIG. 2 shows a partially cross-sectional view of the contact arrangementand the roller-type contact shown in FIG. 1.

FIG. 3 shows an alternative exemplary embodiment of the contactarrangement according to the invention and of the roller-type contactaccording to the invention.

FIG. 4 shows a partially cross-sectional end view of the contactarrangement and of the roller-type contact shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a perspective illustration of an exemplary embodiment ofthe contact arrangement 1 according to the invention using roller-typecontacts 2 according to the invention, in which there is a transparentillustration of a stationary, outer conduit 3 in order also to be ableto illustrate components which are arranged hidden in its interior.

The contact arrangement 1 comprises the stationary conduit 3 as an outercontact piece and a contact bolt 5, which is guided such that it canmove in the longitudinal direction and protrudes into a cutout 4 in theconduit 3, as the inner contact piece. Supported on the conduit 3 andthe contact bolt 5 are in each case rolling bodies 6 of the roller-typecontact 2 composed of two or more contact rollers 7. The contact rollers7 are fixedly connected to one another via a connection device 8. Theconnection device 8 expediently acts on the rotation axes described inmore detail later on and is connected to said rotation axes such that itis secure against rotation. In such an embodiment, each contact roller 7has two compression springs 9 which are each supported on the connectiondevice 8 and on the roller body 6.

For accommodating the roller-type contacts 2, the contact bolt 5 haslongitudinal grooves 10 which have a curvature in cross section.

In order to prevent the roller-type contacts 2 from sliding away fromthe contact bolt 5, a locking limit flange 11 is provided at the end ofsaid contact bolt 5.

FIG. 2 shows a cross-sectional end view of the contact arrangement 1 andthe roller-type contacts 2 shown in FIG. 1. It can be seen in thisillustration that the rolling bodies 6 of the contact rollers 7 arefrustoconical and have a flattened contact-free tip. The longitudinalgroove 10 in the contact bolt 5 has a curvature. In other words, itdelimits a circle segment, the radius of this circle segment or thiscurvature essentially corresponding to the radius of the envelope of thefrustoconical rolling bodies 6 and thus the inner radius of the conduit3.

FIG. 3 shows a perspective illustration of a further exemplaryembodiment of the contact arrangement 1 according to the inventionhaving the roller-type contacts 2 according to the invention. The innercontact piece 5 shown here is no longer cylindrical but has a contourwhich is star-shaped in cross section and a central through-opening 12which is provided for the purpose of connecting extension means such asconnecting rods or the like. When viewed in more detail, the innercontact piece 5 has webs 13 which form an angle with one another of 60°.In this case, the webs 13 merge into one another so as to form an arc,whereby they delimit longitudinal grooves 10. The longitudinal grooves10 are thus curved in cross section, the radius of this curvature beingmatched to the contour of the collar-shaped rolling bodies 6 of thecontact rollers 7. The fact that the inner contact piece 5 which ismoveable in its longitudinal direction is supported and guided threetimes in the cutout 4 in the conduit 3 increases the stability of thecontact arrangement 1.

FIG. 4 shows a partially sectioned end view of the contact arrangement 1shown in FIG. 3. In particular in this view, it can be seen that therolling bodies 6 are pushed loosely onto rigid rotation axes 14, withthe result that the compression spring comprising disk springs 9arranged in a row presses the rolling bodies 6 against the inner wall ofthe conduit 3 and the inner contact piece 5 arranged in the cutout 4.

Naturally, it also possible in the context of the invention to providesecuring flanges on the rotation axis 14 which engage in cutouts in therolling bodies 6 which are expediently included but are not illustratedin the figures, with the result that, on the one hand, a contact roller7 is prevented from falling over when it is removed from the conduit,and, on the other hand, the rolling bodies 6 on the rotation axis 14 aredisplaced to a sufficient extent to produce the pressure.

In the exemplary embodiment illustrated in FIG. 4, a connection means isdispensed with. The disk springs arranged in a row merely form acompression spring 9.

List of Reference Numerals

-   -   1 Contact arrangement    -   2 Roller-type contacts    -   3 Conduit    -   4 Cutout    -   5 Inner contact piece, contact bolt    -   6 Rolling bodies    -   7 Contact roller    -   8 Connection means    -   9 Compression spring    -   10 Longitudinal groove    -   11 Limit flange    -   12 Through-opening    -   13 Web    -   14 Rotation axis

1. A contact arrangement, comprising: at least one outer contact pieceand at least one inner contact piece, which are guided to move in alongitudinal direction with respect to one another; and a roller-typecontact, which has contact rollers and is arranged between the innercontact piece and the outer contact piece forming an electricallyconductive connection, wherein the at least one of the outer contactpiece has a cutout having a limit wall which is concave in crosssection, roller-type contact being arranged at least partially in thecutout for transferring the current.
 2. The contact arrangement asclaimed in claim 1, wherein the outer contact piece is a stationarycontact tube, in which the inner contact piece is arranged as a contactbolt which is guided to move in the longitudinal direction.
 3. Thecontact arrangement as claimed in claim 2, wherein the contact bolt has,at mutually opposing ends, longitudinal grooves which are concave incross section and are each provided for accommodating contact rollers.4. The contact arrangement as claimed in claim 1, wherein the outercontact piece is a stationary contact tube, in which the inner contactpiece is guided to move in the longitudinal direction, the inner contactpiece having a contour which is star-shaped in cross section, such thatsubregions are delimited between the inner contact piece and the contacttube, contact rollers being arranged in the subregions.
 5. The contactarrangement as claimed in claim 3, wherein each longitudinal groove hasa curvature in cross section, whose radius is equal to an inner radiusof the contact tube.
 6. A roller-type contact for making contact betweenat least one outer contact piece and at least one inner contact piece,which are guided to move in a displacement direction with respect to oneanother, the roller-type contact having at least one contact rollerwhich has rolling bodies, which rest against the at least one of outercontact pieces and against at least of the inner contact pieces andconnects the outer and inner contact pieces electrically conductively toone another, at least one spring element for providing a pressure forcefor the rolling bodies, and a rotation axis, wherein the spring elementis a compression spring which is arranged between the rolling bodies. 7.The roller-type contact as claimed in claim 6, wherein the rollingbodies are in a form of collars.
 8. The roller-type contact as claimedin claim 6, wherein the rolling bodies are frustoconical.
 9. Theroller-type contact as claimed in claim 6, wherein two or more contactrollers are provided which are connected to one another via a connectiondevice.